title: Characteristics of oncolytic vesicular stomatitis virus displaying tumor-targeting ligands.
abstract: We sought proof of principle that tumor-targeting ligands can be displayed on the surface of vesicular stomatitis virus (VSV) by engineering its glycoprotein. Here, we successfully rescued VSVs displaying tumor vasculature-targeting ligands. By using a rational approach, we investigated various feasible insertion sites on the G protein of VSV (VSV-G) for display of tumor vasculature-targeting ligands, cyclic RGD (cRGD) and echistatin. We found seven sites on VSV-G that tolerated insertion of the 9-residue cRGD peptide, two of which could tolerate insertion of the 49-amino acid echistatin domain. All of the ligand-displaying viruses replicated as well as the parental virus. In vitro studies demonstrated that the VSV-echistatin viruses specifically bound to targeted integrins. Since the low-density lipoprotein receptor (LDLR) was recently identified as a major receptor for VSV, we investigated the entry of ligand-displaying viruses after masking LDLR. The experiment showed that the modified viruses can enter the cell independently of LDLR, whereas entry of unmodified virus is significantly blocked by a specific monoclonal antibody against LDLR. Both parental and ligand-displaying viruses displayed equal oncolytic efficacies in a syngeneic mouse myeloma model. We further demonstrated that single-chain antibody fragments against tumor-specific antigens can be inserted at the N terminus of the G protein and that corresponding replication-competent VSVs can be rescued efficiently. Overall, we demonstrated that functional tumor-targeting ligands can be displayed on replication-competent VSVs without perturbing viral growth and oncolytic efficacy. This study provides a rational foundation for the future development of fully retargeted oncolytic VSVs.
authors.affiliation: Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Arun
authors.initials: A
authors.lastname: Ammayappan
authors.forename: Kah-Whye
authors.initials: KW
authors.lastname: Peng
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Russell
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D005260:Female; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D008024:Ligands; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D009369:Neoplasms / Q000628:therapy* / Q000821:virology; D050130:Oncolytic Virotherapy; D050504:Oncolytic Viruses / Q000235:genetics* / Q000502:physiology; D010455:Peptides / Q000235:genetics* / Q000378:metabolism; D010456:Peptides, Cyclic / Q000235:genetics* / Q000378:metabolism; D015202:Protein Engineering; D014721:Vesicular stomatitis Indiana virus / Q000235:genetics* / Q000502:physiology; D014759:Viral Envelope Proteins / Q000235:genetics / Q000378:metabolism; D053586:Virus Internalization
chemical_list: C028391:G protein, vesicular stomatitis virus; D036341:Intercellular Signaling Peptides and Proteins; D008024:Ligands; D008562:Membrane Glycoproteins; D010455:Peptides; D010456:Peptides, Cyclic; D014759:Viral Envelope Proteins; C507169:cyclic arginine-glycine-aspartic acid peptide; C057986:echistatin